One hundred years ago this month, Albert Einstein published his theory of general relativity, one of the most important scientific achievements in the last century.

A key result of Einstein’s theory is that matter warps space-time, and thus a massive object can cause an observable bending of light from a background object. The first success of the theory was the observation, during a solar eclipse, that light from a distant background star was deflected by the predicted amount as it passed near the sun.

Astronomers have since found many examples of this phenomenon, known as “gravitational lensing.” More than just a cosmic illusion, gravitational lensing provides astronomers with a way of probing extremely distant galaxies and groups of galaxies in ways that would otherwise be impossible even with the most powerful telescopes.

The latest results from the “Cheshire Cat” group of galaxies show how manifestations of Einstein’s 100-year-old theory can lead to new discoveries today. Astronomers have given the group this name because of the smiling cat-like appearance. Some of the feline features are actually distant galaxies whose light has been stretched and bent by the large amounts of mass, most of which is in the form of dark matter detectable only through its gravitational effect, found in the system.

More specifically, the mass that distorts the faraway galactic light is found surrounding the two giant “eye” galaxies and a “nose” galaxy. The multiple arcs of the circular “face” arise from gravitational lensing of four different background galaxies well behind the “eye” galaxies. The individual galaxies of the system, as well as the gravitationally lensed arcs, are seen in optical light from NASA’s Hubble Space Telescope.

Each “eye” galaxy is the brightest member of its own group of galaxies and these two groups are racing toward one another at over 300,000 miles per hour. Data from NASA’s Chandra X-ray Observatory (purple) show hot gas that has been heated to millions of degrees, which is evidence that the galaxy groups are slamming into one another. Chandra’s X-ray data also reveal that the left “eye” of the Cheshire Cat group contains an actively feeding supermassive black hole at the center of the galaxy.

Astronomers think the Cheshire Cat group will become what is known as a fossil group, defined as a gathering of galaxies that contains one giant elliptical galaxy and other much smaller, fainter ones. Fossil groups may represent a temporary stage that nearly all galaxy groups pass through at some point in their evolution. Therefore, astronomers are eager to better understand the properties and behavior of these groups.

The Cheshire Cat represents the first opportunity for astronomers to study a fossil group progenitor. Astronomers estimate that the two “eyes” of the cat will merge in about one billion years, leaving one very large galaxy and dozens of much smaller ones in a combined group. At that point it will have become a fossil group and a more appropriate name may be the “Cyclops” group.

When computers hit the mainstream, the older guy in the office would always be sniggered at when bashing away on his QWERTY keyboard, only using his two index fingers to type. To the amusement of his younger, tech-savvy colleagues, he would almost look Neanderthal next to those who grew up with computers and used all their fingers on the keyboard quickly and fluently.

During the 1970s, scientists confirmed that radio emissions coming from the center of our galaxy were due to the presence of a Supermassive Black Hole (SMBH). Located about 26,000 light-years from Earth between the Sagittarius and Scorpius constellation, this feature came to be known as Sagittarius A*. Since that time, astronomers have come to understand that most massive galaxies have an SMBH at their center.

A new paper outlines objectives Scotland should strive to meet if it wants to emerge a world leader in renewable energy. The nation is already making progress toward that goal, thanks to an increased use of wind power and pledges to phase out fossil fuels.

Astronomers have discovered the most distant supernova yet, at a distance of 10.5 billion light years from Earth. The supernova, named DES16C2nm, is a cataclysmic explosion that signaled the end of a massive star some 10.5 billion years ago. Only now is the light reaching us. The team of astronomers behind the discovery have published their results in a new paper available at arXiv.

Researchers have developed a new device that can generate electricity from figure movement by harnessing triboelectric charging. This tiny tab could one day allow us to charge our devices without having to plug them into an outlet.

It’s been a time of milestones for Mars rovers lately! Last month (on January 26th, 2018), NASA announced that the Curiosity rover had spent a total of 2,000 days on Mars, which works out to 5 years, 5 months and 21 days. This was especially impressive considering that the rover was only intended to function on the Martian surface for 687 days (a little under two years).

Since ancient times, astronomers have looked up at the night sky and seen the Andromeda galaxy. As the closest galaxy to our own, scientists have been able to observe and scrutinize this giant spiral galaxy for millennia. By the 20th century, astronomers realized that Andromeda was the Milky Way’s sister galaxy and was moving towards us. In 4.5 billion years, it will even merge with our own to form a supergalaxy.

While analyzing hundreds of soil samples, researchers from Rockefeller University discovered a new family of antibiotics. These compounds could help tremendously in the fight against antibiotic resistance.